Sealing Masonry Joints To Make Them Airtight And Watertight

Procedure code:
Fed Bldg/Uspo/Spokane, Wa - Gsa/Pbs, 3-11-91
Thermal and Moisture Protection
Joint Sealers
Last Modified:





    A.   This procedure includes guidance on installing joint
         sealers at masonry joints for the following locations:

         1.   Exterior joints in vertical surfaces and non-
              traffic horizontal surfaces; these may include
              perimeter joints at frames of doors and windows.

         2.   Exterior joints in horizontal traffic surfaces;
              these may include joints in stone steps (see also

         3.   Interior joints in vertical surfaces and horizontal
              non-traffic surfaces; these may include perimeter
              joints between interior wall surfaces and frames of
              interior doors, windows and elevator entrances, or
              perimeter joints of toilet fixtures.

         4.   Interior joints in horizontal traffic surfaces;
              these may include joints in stone steps.

    B.   For guidance on selecting joint sealants for masonry,
         based on composition, elasticity and durability, see
         07900-01-S "Criteria For Selecting Masonry Joint


    A.   American Society for Testing and Materials (ASTM), 100
         Barr Drive, West Conshohocken, PA 19428, (610) 832-9585
         or FAX (610) 832-9555.


    A.   Provide joint sealers that have been produced and
         installed to establish and maintain watertight and
         airtight continuous seals.


    A.   Product Data from manufacturer's for each joint sealer
         product required, including instructions for joint
         preparation and joint sealer application.

    B.   Samples of each type and color of joint sealer required.
         Install joint sealer samples in 1/2" wide joints formed
         between two 6" long strips of material matching the
         appearance of exposed surfaces adjacent to joint sealers.

    C.   Certificates from manufacturers of joint sealers
         attesting that their products comply with specification
         requirements and are suitable for the use indicated.


    A.   Installer Qualifications:  Engage an Installer who has
         successfully completed within the last 3 years at least
         3 joint sealer applications similar in type and size to
         that of this project.

    B.   Single Source Responsibility for Joint Sealer Materials:
         Obtain joint sealer materials from a single manufacturer
         for each different product required.

    C.   Preconstruction Field Testing:  Prior to installation of
         joint sealants, field-test their adhesion to joint
         substrates as follows:

         1.   Conduct field tests for each application indicated

              a.   Each type of elastomeric sealant and joint
                   substrate indicated.

              b.   Each type of non-elastomeric sealant and joint
                   substrate indicated.

         2.   Arrange for tests to take place with both RHPO and
              joint sealer manufacturer's technical
              representative present.

         3.   Test Method:  Test joint sealers by hand pull
              method described below:

              a.   Install joint sealants in 5-feet joint lengths
                   using same materials and methods required for
                   joint preparation and joint sealant
                   installation required for completed work.
                   Allow sealants to cure fully before testing.

              b.   Make knife cuts as follows:  A horizontal cut
                   from one side of joint to the other followed
                   by 2 vertical cuts approximately 2" long at
                   side of joint and meeting horizontal cut at
                   top of 2" cuts.  Place a mark 1" from top of
                   2" piece.

              c.   Use fingers to grasp 2" piece of sealant just
                   above 1" mark; pull firmly down at a 90 degree
                   angle or more while holding a ruler along side
                   of sealant.  Pull sealant out of joint to the
                   distance recommended by sealant manufacturer
                   for testing adhesive compatibility, but not
                   less than that equaling specified maximum
                   movement capability in extension; hold this
                   position for 10 seconds.

         4.   Report whether or not sealant in joint connected to
              pulled-out portion failed to adhere to joint
              substrates or tore cohesively.  Include data on
              pull distance used to test each type of product and
              joint substrate.

         5.   Evaluation of Field Test Results:  Sealants not
              evidencing adhesive failure from testing, in
              absence of other indications of noncompliance with
              requirements, will be considered satisfactory.  Do
              not use sealants which fail to adhere to joint
              substrates during testing.

    D.   Pre-Installation Meeting:  At contractor's direction,
         installer, joint sealer manufacturers' representatives,
         and other trades whose work affects installation of joint
         sealers shall meet at project site to review procedures
         and time schedule proposed for installation of joint
         sealers which is coordinated with other, related work.


    A.   Acceptance at Site:  Deliver materials to project site in
         original unopened containers or bundles with labels
         informing about manufacturer, product name and
         designation, color, expiration period for use, pot life,
         curing time and mixing instructions for multi-component

    B.   Storage and Protection:  Store and handle materials in
         compliance with manufacturer's recommendations to prevent
         their deterioration or damage due to moisture, high or
         low temperatures, contaminants, or other causes.


    A.   Environmental Conditions:  Do not proceed with
         installation of joint sealers under the following

         1.   When ambient and substrate temperature conditions
              are outside the limits permitted by joint sealer
              manufacturer or below 40 degrees F (4.4 degrees C).

         2.   When joint substrates are wet due to rain, frost,
              condensation or other causes.

    B.   Joint Width Conditions:  Do not proceed with installation
         of joint sealers where joint widths are less than allowed
         by joint sealer manufacturer for application indicated.

    C.   Joint Substrate Conditions:  Do not proceed with
         installation of joint sealers until contaminants capable
         of interfering with their adhesion are removed for joint


    A.   Sequence installation of joint sealers to occur not less
         than 21 nor more than 30 days after completion of
         waterproofing, unless otherwise indicated.



    A.   Bostik Construction Products
         Boston Street
         Middleton, MA  01949
         800/726-7845, FAX 508/774-7376

    B.   Dow Corning Corporation
         1225 Northmeadow Parkway, Ste. 104
         Roswell, GA  30076


         P.O. Box 994
         Midland, MI  48686-0994

    C.   General Electric Co.
         Silicone Products Division
         Waterford, NY  12188

    D.   Mameco International, Inc.
         4475 East 175th Street
         Cleveland, OH  44128

    E.   Pecora Corporation
         165 Wambold Road
         Harleysville, PA  19438
         800/522-1285 or 215/723-6051
         2601 Oakland Avenue
         Garland, TX  75041
         800/523-6688 or 214/278-8158

    F.   Sika Corporation
         201 Polito Ave.
         Lyndhurst, NJ  07071

    G.   3M Consumer Products Group
         Box 33053
         St. Paul, MN  55133-3053
         612/737-6501 or 800/364-3577

    H.   Tremco, Inc.
         3735 Green Rd.
         Beachwood, OH  44122


    A.   For additional guidance on selecting masonry joint
         sealants, see 07900-01-S "Criteria for Selecting Masonry
         Joint Sealants".

    B.   General:

         1.   Compatibility:  Provide joint sealers, joint
              fillers and other related materials that are
              compatible with one another and with joint
              substrates under conditions of service and
              application, as demonstrated by sealant
              manufacturer based on testing and field experience.

         2.   Colors:  Provide color of exposed joint sealer
              indicated or, if not otherwise indicated, as
              selected by Contracting Officer from manufacturer's
              standard colors.

    C.   Elastomeric Joint Sealants:

         1.   Elastomeric Sealant Standard:  Provide
              manufacturer's standard chemically curing,
              elastomeric sealant of base polymer indicated which
              complies with ASTM C920 requirements, including
              those referenced for Type, Grade, Class and Uses.

         2.   One-Part Mildew-Resistant Silicone Sealant such as
              "Dow Corning 786" (Dow Corning Corporation), "SCS
              1702" (General Electric Co.), or approved equal.

              a.   Type S; Grade NS; Class 25

              b.   Uses NT, G, A, and, as applicable to non-porous joint substrate indicated, O

              c.   Formulated with fungicide for sealing interior
                   joints with nonporous substrate around ceramic
                   tile, showers, sinks and plumbing fixtures.

         3.   One-Part Non-sag Urethane Sealant for Use NT such
              as "Chem-Calk 900" or "Chem-Calk 2639" (Bostik
              Construction Products), "Vulkem 116" or "Vulkem
              921" (Mameco International, Inc.), "Sikaflex-1a" or
              "Sikaflex-15LM" (Sika Corporation), or approved

              a.   Type S; Grade NS; Class 25

              b.   Uses NT, M, A, and, as applicable to joint
                   substrates indicated, O.

         4.   One-Part Non-sag Urethane Sealant for Use T such as
              "Chem-Calk 900" (Bostik Construction Products),
              "Sikaflex-1a" or "Sikaflex-15LM" (Sika
              Corporation), or approved equal.

              a.   Type S; Grade P; Class 25.

              b.   Uses T, M, and, as applicable to joint
                   substrates indicated, O.

         5.   One-Part Pourable Urethane Sealant for Use T such
              as "Chem-Calk 950" (Bostik Construction Products)
              "Vulkem 45" (Mameco International, Inc.), or
              approved equal.

    D.   Latex Joint Sealants:

         1.   Acrylic-Emulsion Sealant such as "Chem-Calk 600"
              (Bostik Construction Products), or approved equal.

              a.   Manufacturer's standard, one part, non-sag,
                   acrylic, mildew-resistant, acrylic-emulsion
                   sealant complying with ASTM C834.

              b.   Formulated to be painted and recommended for
                   exposed applications on interior and on
                   protected exterior exposures involving joint
                   movement of not more than + or - 7.5%.

    E.   Acoustical Joint Sealants:

         1.   Acoustical Sealant for Concealed Joints such as
              "BA098" (Pecora Corporation), "Tremco Acoustical
              Sealant" (Tremco, Inc.), or approved equal.

              a.   Manufacturer's standard, non-drying, non-hardening, non-skinning, non-staining,
                   gunnable, synthetic rubber sealant.

              b.   Recommended for sealing interior concealed
                   joints to reduce transmission of airborne

    F.   Fire-Resistant Joint Sealers:

         1.   General:  Provide manufacturer's standard fire-
              stopping sealant, with accessory materials, having
              fire-resistance ratings indicated as established by
              testing identical assemblies per ASTM E814 by
              Underwriters Laboratory, Inc. or other testing and
              inspecting agency acceptable to authorities having

         2.   Foamed-In-Place Fire-Stopping Sealant such as "Dow
              Corning Fire Stop Foam" (Dow Corning Corporation),
              "Pensil 851" (General Electric Co.), or approved

              a.   Two-part, foamed-in-place, silicone sealant
                   formulated for use in a through-penetration
                   fire-stop system.

              b.   For filling openings around cables, conduit,
                   pipes and similar penetrations through walls
                   and floors.

         3.   One-Part Fire-Stopping Sealant such as "Dow Corning
              Fire Stop Sealant" (Dow Corning Corporation), "3M
              Fire Barrier Caulk CP-25" (Electrical Products
              Div./3M), "RTV 7403" (General Electric Co.), or
              approved equal.

              a.   One-part elastomeric sealant formulated for
                   use in a through-penetration fire-stop system.

              b.   For sealing openings around cables, conduit,
                   pipes and similar penetrations through walls
                   and floors.

    G.   Joint Sealant Backing:

         1.   General:  Provide sealant backings of material and
              type which are non-staining; are compatible with
              joint substrates, sealants, primers and other joint
              fillers; and are approved for applications
              indicated by sealant manufacturer based on field
              experience and laboratory testing.

         2.   Plastic Foam Joint Fillers:  Preformed,
              compressible, resilient, non-waxing, non-extruding
              strips of flexible, non-gassing plastic foam of
              material indicated below;  non-absorbent to water
              and gas; and of size, shape and density to control
              sealant depth and otherwise contribute to producing
              optimum sealant performance.

              a.   Either open cell polyurethane foam or closed-
                   cell polyethylene foam, unless otherwise
                   indicated, subject to approval of sealant
                   manufacturer, for cold-applied sealants only.

              b.   Elastomeric Tubing Joint-Fillers:  Neoprene,
                   butyl or EPDM tubing complying with ASTM
                   D1056, non-absorbent to water and gas, capable
                   of remaining resilient at temperatures down to
                   -26 degrees F (-15 degrees C).  Provide
                   products with low compression set and of size
                   and shape to provide a secondary seal, to
                   control sealant depth and otherwise contribute
                   to optimum sealant performance.

         3.   Bond-Breaker Tape:  Polyethylene tape or other
              plastic tape as recommended by sealant manufacturer
              for preventing sealant from adhering to rigid,
              inflexible joint filler materials or joint surfaces
              at back of joint where such adhesion would result
              in sealant failure.  Provide self-adhesive tape
              where applicable.

    H.   Miscellaneous Materials:

         1.   Primer:  Provide type recommended by joint sealer
              manufacturer where required for adhesion of sealant
              to joint substrates indicated, as determined from
              preconstruction joint sealer substrate tests and
              field tests.

         2.   Cleaners for Nonporous Surfaces:  Provide non-
              staining, chemical cleaners of type which are
              acceptable to manufacturer of sealants and sealant
              backing materials, which are not harmful to
              substrates and adjacent non-porous materials, and
              which do not leave oily residues or otherwise have
              a detrimental effect on sealant adhesion or in-
              service performance.

         3.   Masking Tape:  Provide non-staining, non-absorbent
              type compatible with joint sealants and to surfaces
              adjacent to joints.

         4.   Accessory materials for Fire-Stopping Sealants:
              Provide forming, joint-fillers, packing and other
              accessory materials required for installation of
              fire-stopping sealants as applicable to
              installation conditions indicated.

    I.   Joint Fillers for Concrete Paving:

         1.   General:  Provide joint fillers of thickness and
              widths indicated.

         2.   Bituminous Fiber Joint Filler:  Preformed strips of
              composition below, complying with ASTM D1751:

              a.   Asphalt saturated fiberboard.



    A.   Examine joints indicated to receive joint sealers, with
         installer present, for compliance with requirements for
         joint configuration, installation tolerances and other
         conditions affecting joint sealer performance.  Do not
         proceed with installation of joint sealers until
         unsatisfactory conditions have been corrected.


    A.   Surface Preparation:

         1.   Joint and Surface Cleaning:

              a.   Clean out joints immediately before installing
                   joint sealers to comply with recommendations
                   of joint sealer manufacturers and the
                   following requirements:

              b.   Remove all foreign material from joint
                   substrates which could interfere with adhesion
                   of joint sealer, including dust; paints,
                   except for permanent, protective coatings
                   tested and approved for sealant adhesion and
                   compatibility by sealant manufacturer; old
                   joint sealers; oil; grease; waterproofing;
                   water repellents; water; surface dirt and

              c.   Clean concrete, masonry, unglazed surfaces of
                   ceramic tile and similar porous joint
                   substrate surfaces, by brushing, grinding,
                   blast cleaning, mechanical abrading, or a
                   combination of these methods to produce a
                   clean, sound substrate capable of developing
                   optimum bond with joint sealers.  Remove loose
                   particles remaining from above cleaning
                   operations by vacuuming or blowing out joints
                   with oil-free compressed air.

              d.   Remove laitance and form release agents from

              e.   Clean metal, glass, porcelain enamel, glazed
                   surfaces of ceramic tile and other non-porous
                   surfaces by chemical cleaners or other means
                   which are not harmful to substrates or leave
                   residues capable of interfering with adhesion
                   of joint sealers.

         2.   Joint Priming:  Prime joint substrates where
              indicated or where recommended by joint sealer
              manufacturer based on preconstruction joint sealer-
              substrate tests or prior experience.  Apply primer
              to comply with joint sealer of manufacturer's
              recommendations.  Confine primers to areas of joint
              sealer bond, do not allow spillage or migration
              onto adjoining surfaces.

         3.   Masking Tape:  Use masking tape where required to
              prevent contact of sealant with adjoining surfaces
              which otherwise would be permanently stained or
              damaged by such contact or by cleaning methods
              required to remove sealant smears.  Remove tape
              immediately after tooling without disturbing joint


    A.   General:  Comply with joint sealer manufacturers' printed
         installation instructions applicable to products and
         applications indicated, except where more stringent
         requirements apply.

    B.   Elastomeric Sealant Installation Standard:  Comply with
         recommendations of ASTM C962 for use of joint sealants as
         applicable to materials, applications and conditions

    C.   Latex Sealant Installation Standard:  Comply with
         requirements of ASTM C790 for use of latex sealants.

    D.   Installation of Sealant Backings:  Install sealant
         backings to comply with the following requirements:

         1.   Install joint-fillers of type indicated to provide
              support of sealants during application and at
              position required to produce the cross-sectional
              shapes and depths of installed sealants relative to
              joint widths which allow optimum sealant movement

              a.   Do not leave gaps between ends of joint-fillers.

              b.   Do not stretch, twist, puncture or tear joint

              c.   Remove absorbent joint fillers which have
                   become wet prior to sealant application and
                   replace with dry material.

         2.   Install bond breaker tape between sealants and
              joint-fillers, compression seals or back of joints
              where adhesion of sealant to surfaces at back of
              joints would result in sealant failure.

    E.   Installation of Sealants:  Install sealants by proven
         techniques that result in sealants directly contacting
         and fully wetting joint substrates, completely filling
         recesses provided for each joint configuration and
         providing uniform, cross-sectional shapes and depths
         relative to joint widths which allow optimum sealant
         movement capability.

    F.   Tooling of Non-sag Sealants:  Immediately after sealant
         application and prior to time skinning or curing begins,
         tool sealants to form smooth, uniform beads of
         configuration indicated, to eliminate air pockets and to
         ensure contact and adhesion of sealant with sides of
         joint.  Remove excess sealants from surfaces adjacent to
         joint.  Do not use tooling agents which discolor sealants
         or adjacent surfaces or are not approved by sealant

         1.   Provide concave joint configuration per Figure 6A
              in ASTM C962, unless otherwise indicated.

              a.   Use masking tape to protect adjacent surfaces
                   of recessed tooled joints.

    G.   Pourable sealants shall be applied by gun or by pouring,
         filling the joint completely with a slight recessed
         finish.  Additional material will be added if low spots

    H.   Installation of Fire-Stopping Sealant:  Install sealant,
         including forming, packing and other accessory materials
         to fill openings around mechanical and electrical
         services penetrating floors and walls to provide fire-
         stops with fire resistance ratings indicated for floor or
         wall assembly in which penetration occurs.  Comply with
         installation requirements established by testing and
         inspecting agency.


    A.   Clean off excess sealants or sealant smears adjacent to
         joints as work progresses by methods and with cleaning
         materials approved by manufacturers of joint sealers and
         of products in which joints occur.


    A.   Protect joint sealers during and after curing period from
         contact with contaminating substances or from damage
         resulting from construction operations or other causes so
         that they are without deterioration or damage at time of
         substantial completion.  If, despite such protection,
         damage or deterioration occurs, cut out and remove
         damaged or deteriorated joint sealers immediately and
         reseal joints with new materials to produce joint sealer
         installations with repaired areas indistinguishable from
         original work.

                         END OF SECTION
Last Reviewed 2012-02-24